The present invention relates generally to actuator arms found in hard disk drives.
Conventional hard disk drives include multiple storage disks having read/write surfaces on which data is stored. These disk drives also include multiple actuator arms, e.g., one actuator arm for each disk. Each actuator arm supports a read/write head. The read/write heads are used to read data from or write data to the storage disks. When fully operational, server class disk drives may read or write data for relatively long periods of time before being shut down. In the case of load/unload drives, the sliders that support the read/write heads may not be unloaded from the disk surface for several months at a time. If the read/write heads are not unloaded from the disk, the actuator arms do not have a chance to move beyond the outer diameter of the storage disks. Consequently, grease can accumulate in the actuator bearings just beyond the outer limits of motion of the actuator arms during the extended read/write session.
The actuator arms must overcome the accumulated grease when unloading after an extended load period. Typically, this is not troublesome if the unload sequence is servo-controlled. However, if the drive is shut down and the unloading is driven by the hardware unload algorithm, i.e., open loop control, the actuator arms may not overcome the accumulated grease. As a result, the sliders may not fully unloadxe2x80x94if they unload at all. Accordingly, there is a need to periodically reduce the accumulation of grease in the actuator bearings.
A method for reducing the accumulation of actuator bearing grease in a disk drive includes monitoring an elapsed disk drive operating time. Based on the monitoring act, the actuator is forced through one or more unload/load cycles. In a preferred embodiment, a current required to unload the disk drive is monitored and it is determined whether the current is within a predetermined range of current operating levels. If the current falls outside the predetermined range, the frequency of the unload/load cycles is adjusted. Preferably, the unload/load cycle is repeated a predetermined number of times. Moreover, in a preferred embodiment, the elapsed time is an elapsed time without a disk unload.
In another aspect of the present invention, a disk drive includes a disk that has a read/write surface. The disk drive also includes an actuator arm that supports a read/write head. The actuator arm is rotatably mounted on an actuator bearing and the read/write bead moves across the read/write surface as the actuator arm rotates. In this aspect, the disk drive includes a controller that includes a computer program that has logic means for reducing the accumulation of grease in the actuator bearing.
In yet another aspect of the present invention, a computer program device includes means for forcing at least one unload/load cycle in a disk drive to ameliorate grease build-up.
The preferred embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: